The present invention generally relates to methods and systems for providing adaptive optics, and in particular to methods and systems for providing adaptive optics using amplitude and phase.
Typical adaptive optics systems utilize deformable mirror (DM) actuators to compensate for the optical effects introduced by the turbulence in the Earth's atmosphere and distortions produced by the optical elements between the distant object and its local sensors. Such adaptive optics systems command the DM actuators while minimizing the measured wavefront phase error and set the DM actuators so that the outgoing laser's phase is opposite that of an incoming beacon. The disadvantage of the foregoing technique is that it does not work well in a strong turbulent or scintillation condition because the amplitude attenuation along the propagation path is not compensated.
One proposed system resolves the foregoing problem by using a dual-DM to compensate both amplitude and phase. This proposed system only uses the phase error to generate commands to both DMs. The corrections for both DMs are calculated based on the phase difference between the outgoing and the returned laser beams. The foregoing technique is near optimal only if the distance between the DMs is the same as the optical distance to the strongest turbulent layer.
Hence, it would be desirable to provide methods and systems that are capable of handling adaptive optics using amplitude and phase.